I need some advice on toilet training, please....

My son is 4. He pees in the toilet, he won't poop in the toilet. If he needs to poop he wants a diaper. He has gone 3 or so days without pooping if he doesn't get a diaper. He is very aware of the situation, we talk about it a lot. I have tried to bribe him but no dice. I have brand new toys on the self in the bathroom. A space ship, remote control trucks, a fishing pole. He wants the toys and knows how to get them but no dice. He even gets small toys just to sit on the toilet but I feel like I am forcing him to to even that.

Do I hold out? Do I just give him the toys? Maybe it will empower him.

Any advice or similar stories would be greatly appreciated.